1. Field of the Invention
This invention relates to a method of cleaning a conduit including downpipe, by which a cleaning tool to be rotatingly driven via a flexible shaft, in particular a helical spring, is subjected to a longitudinal feed extending in conduit direction for removing deposits in the pipe, while at the same time flushing water is allowed to flow into the conduit for carrying away the cuttings above the removal area, and below the removal area flushing water is injected into the conduit in outflow direction with excess pressure.
2. Description of the Prior Art
Conduits, in particular sewer and drain pipes, are more and more constricted in their inside flow cross-section due to soiling and encrustation, until the amounts of water produced can no longer flow off and there is a backpressure and as a result thereof damages caused by water. In order to remedy this problem and prevent the conduit from clogging or to clear a clogged pipe, there already exist cleaning methods where the deposits are worked off mechanically and swept away. For this purpose, a chain centrifuge serving as cleaning tool and rotating via a drivable helical spring is introduced from the top into a downpipe of a conduit to be cleaned, where the chain parts of the chain centrifuge strike against the deposits and work off the deposits on the wall. However, these chain centrifuge tools can hardly be metered in their effect, the conduits are subjected to a considerable, often already damaging impact load, and the tool advanced substantially due to gravity is hardly able to overcome curvatures of the conduit, as they frequently occur for instance as gravity brakes in higher downpipes or in the case of mutually offset pipe sections. In addition, due to the impact effect of the chain centrifuge relatively coarse pieces and plate-shaped parts of the hard deposits are detached and blasted off, which fall downwards and/or are swept along with the flushing water and advance into the yet uncleaned, constricted pipe, where cloggings caused by the cuttings are then virtually inevitable. The newly introduced water or waste water flowing into the downpipe can no longer flow off, and there is a risk of backpressure along with the great consequential damages. The known cleaning methods therefore remain unsatisfactory and can only be used successfully in simple cases because of the involved risk of a damage exceeding the benefits.
Moreover, there already exist all kinds of cleaning methods for cleaning horizontal conduits, which methods employ milling cutters such as rotary water milling cutters (DE 44 16 721 C), root milling heads (DE 34 27 371 A) or the like, which are drawn in feed direction or advanced via an ejection of pressurized water, which methods are, however, not suited for cleaning strongly encrusted downpipes. Furthermore, there are known methods for expanding the inside cross-section of a chimney (DE 195 30 880 A), where milling heads with stepped diameters are introduced into the chimney from the top, which methods cannot be used for cleaning downpipes of a conduit, as pipe curvatures cannot be taken into account and the risk of clogging by the detached cuttings would be too great.